I've had an account with N2P since their early days. Even used their calling card. The audio quality is just average. The CommCenter product does not work on Vista. On XP, faxes were in the pending status for over a day! Emails to customer support go unanswered. I ask to close the account and the money refunded. If you cannot respond in four days, then I need to go elsewhere.
Update: Still no response to emails sent months ago. I do not suggest using this company at all.
December 2012 - I finally got a refund for the money I had on deposit with them. They seem to be fully concentrating on the business market as you don't see them much in the consumer area or anyone even talking about them on DSLR.